diff --git a/chash.c b/chash.c
index 5c3148b..b8c1fec 100644
--- a/chash.c
+++ b/chash.c
@@ -10,6 +10,8 @@
 #define u_char  unsigned char
 #endif
 
+#define CHASH_OK    0
+#define CHASH_ERR   -1
 
 #define crc32_final(crc)                                                  \
     crc ^= 0xffffffff
@@ -144,7 +146,7 @@ chash_point_init(chash_point_t *arr, uint32_t base_hash, uint32_t start,
 }
 
 
-void
+int
 chash_point_sort(chash_point_t arr[], uint32_t n)
 {
     chash_point_t *points;
@@ -163,6 +165,9 @@ chash_point_sort(chash_point_t arr[], uint32_t n)
     step = pow(2, 32) / m;
 
     points = (chash_point_t *) calloc(m, sizeof(chash_point_t));
+    if (points == NULL) {
+        return CHASH_ERR;
+    }
 
     for (i = 0; i < n; i++) {
         node = &arr[i];
@@ -246,10 +251,12 @@ chash_point_sort(chash_point_t arr[], uint32_t n)
     }
 
     free(points);
+
+    return CHASH_OK;
 }
 
 
-void
+int
 chash_point_add(chash_point_t *old_points, uint32_t old_length,
     uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id,
     chash_point_t *new_points)
@@ -258,9 +265,16 @@ chash_point_add(chash_point_t *old_points, uint32_t old_length,
     chash_point_t *tmp_points;
 
     tmp_points = (chash_point_t *) calloc(num, sizeof(chash_point_t));
+    if (tmp_points == NULL) {
+        return CHASH_ERR;
+    }
 
     chash_point_init_crc(tmp_points, 0, base_hash, from, num, id);
-    chash_point_sort(tmp_points, num);
+
+    if (chash_point_sort(tmp_points, num) != CHASH_OK) {
+        free(tmp_points);
+        return CHASH_ERR;
+    }
 
     j = num - 1;
     k = old_length + num - 1;
@@ -283,10 +297,12 @@ chash_point_add(chash_point_t *old_points, uint32_t old_length,
     }
 
     free(tmp_points);
+
+    return CHASH_OK;
 }
 
 
-void
+int
 chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
     uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id)
 {
@@ -296,7 +312,11 @@ chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
     tmp_points = (chash_point_t *) calloc(num, sizeof(chash_point_t));
 
     chash_point_init_crc(tmp_points, 0, base_hash, from, num, id);
-    chash_point_sort(tmp_points, num);
+
+    if (chash_point_sort(tmp_points, num) != CHASH_OK) {
+        free(tmp_points);
+        return CHASH_ERR;
+    }
 
     for (i = 0, j = 0, k = 0; i < old_length; i++) {
         if (j < num
@@ -315,6 +335,8 @@ chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
     }
 
     free(tmp_points);
+
+    return CHASH_OK;
 }
 
 
diff --git a/chash.h b/chash.h
index b7f864c..8fb97b0 100644
--- a/chash.h
+++ b/chash.h
@@ -39,12 +39,12 @@ typedef struct {
  */
 void chash_point_init(chash_point_t *points, uint32_t base_hash,
     uint32_t start, uint32_t num, uint32_t id) LCH_EXPORT;
-void chash_point_sort(chash_point_t *points, uint32_t npoints) LCH_EXPORT;
+int chash_point_sort(chash_point_t *points, uint32_t npoints) LCH_EXPORT;
 
-void chash_point_add(chash_point_t *old_points, uint32_t old_length,
+int chash_point_add(chash_point_t *old_points, uint32_t old_length,
     uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id,
     chash_point_t *new_points) LCH_EXPORT;
-void chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
+int chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
     uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id) LCH_EXPORT;
 void chash_point_delete(chash_point_t *old_points, uint32_t old_length,
     uint32_t id) LCH_EXPORT;
diff --git a/lib/resty/chash.lua b/lib/resty/chash.lua
index 90e73bc..930ebad 100644
--- a/lib/resty/chash.lua
+++ b/lib/resty/chash.lua
@@ -19,6 +19,10 @@ local pairs = pairs
 local tostring = tostring
 local tonumber = tonumber
 local bxor = bit.bxor
+local error = error
+
+
+local CHASH_OK = 0
 
 
 ffi.cdef[[
@@ -31,12 +35,12 @@ typedef struct {
 
 void chash_point_init(chash_point_t *points, uint32_t base_hash, uint32_t start,
     uint32_t num, uint32_t id);
-void chash_point_sort(chash_point_t *points, uint32_t size);
+int chash_point_sort(chash_point_t *points, uint32_t size);
 
-void chash_point_add(chash_point_t *old_points, uint32_t old_length,
+int chash_point_add(chash_point_t *old_points, uint32_t old_length,
     uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id,
     chash_point_t *new_points);
-void chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
+int chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
     uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id);
 void chash_point_delete(chash_point_t *old_points, uint32_t old_length,
     uint32_t id);
@@ -117,7 +121,9 @@ local function _precompute(nodes)
         start = start + num
     end
 
-    clib.chash_point_sort(points, npoints)
+    if clib.chash_point_sort(points, npoints) ~= CHASH_OK then
+        error("no memory")
+    end
 
     return ids, points, npoints, newnodes
 end
@@ -194,14 +200,21 @@ local function _incr(self, id, weight)
     local new_npoints = self.npoints + weight * CONSISTENT_POINTS
     if self.size < new_npoints then
         new_points = ffi_new(chash_point_t, new_npoints)
-        self.size = new_npoints
     end
 
     local base_hash = bxor(crc32(tostring(id)), 0xffffffff)
-    clib.chash_point_add(self.points, self.npoints, base_hash,
-                         old_weight * CONSISTENT_POINTS,
-                         weight * CONSISTENT_POINTS,
-                         index, new_points)
+    local rc = clib.chash_point_add(self.points, self.npoints, base_hash,
+                                    old_weight * CONSISTENT_POINTS,
+                                    weight * CONSISTENT_POINTS,
+                                    index, new_points)
+
+    if rc ~= CHASH_OK then
+        error("no memory")
+    end
+
+    if self.size < new_npoints then
+        self.size = new_npoints
+    end
 
     self.points = new_points
     self.npoints = new_npoints
@@ -230,10 +243,15 @@ local function _decr(self, id, weight)
     end
 
     local base_hash = bxor(crc32(tostring(id)), 0xffffffff)
-    clib.chash_point_reduce(self.points, self.npoints, base_hash,
-                            (old_weight - weight) * CONSISTENT_POINTS,
-                            CONSISTENT_POINTS * weight,
-                            index)
+    local from = (old_weight - weight) * CONSISTENT_POINTS
+    local num = CONSISTENT_POINTS * weight
+
+    local rc = clib.chash_point_reduce(self.points, self.npoints, base_hash,
+                                       from, num, index)
+
+    if rc ~= CHASH_OK then
+        error("no memory")
+    end
 
     nodes[id] = old_weight - weight
     self.npoints = self.npoints - CONSISTENT_POINTS * weight
diff --git a/lib/resty/roundrobin.lua b/lib/resty/roundrobin.lua
index 97743b5..be727d0 100644
--- a/lib/resty/roundrobin.lua
+++ b/lib/resty/roundrobin.lua
@@ -4,6 +4,7 @@ local next = next
 local tonumber = tonumber
 local setmetatable = setmetatable
 local math_random = math.random
+local error = error
 
 local utils = require "resty.balancer.utils"